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ABX: Analyze Pixel Statistics in an Image


\begin{command}
\item[\textbf{Form:}ABX source {[boxes]} {[ALL]} {[W=w1,w2]} {[...
...al reaches
the value farea.}
\item[var]{the name of a variable.}
\end{command}

ABX analyzes the statistics of an image or spectrum. It computes the total, mean, and standard deviation about the mean. It also finds the locations and values of the highest and lowest pixels. The output of this program can be redirected.

To analyze the object in regions defined by boxes, give the NUMBERS of the boxes on the command line. If you give no numbers, the entire image will be analyzed. Alternatively, specify any number of boxes using the BOX=b1,b2,... keyword. Examples:
\begin{example}
\item[ABX 3\hfill]{Finds the properties of object 3 in the enti...
...X 2 BOX=3,4,5,6 \hfill]{Analyzes object 2 in boxes 3, 4, 5, and 6}
\end{example}

Note that in ABX, boxes are specified by integers, and not by BOX= keyword, as is usual in other commands. See BOX to see how to define boxes.

To analyze the entire image or spectrum, use the keyword ALL or simply do not specify a box number. Any box specifiers on the command line are ignored. To analyze part of a wavelength-calibrated spectrum, use W= to specify the part in Angstroms.

ABX finds the image mean, total count over all pixels, values of the highest and lowest pixels, location of the highest and lowest pixels, and the standard deviation of the counts in the pixels about the mean. A table of the results is printed on the output device.

ABX will store the values for the various properties of the image in variables if certain keywords are included on the command line:
\begin{example}
\item[TOTAL=var\hfill]{Stores the total count of all the pixels...
... pixel where the total reaches farea
(using AREA=farea) keyword.}
\end{example}

Examples of storing information in variables are:
\begin{example}
\item[ABX 1 3 MEAN=M3 SIGMA=SIG3\hfill]{Analyzes image 1 in box...
...,
storing the location of the highest-valued pixel in HR and HC}
\end{example}
The use of the variable-setting keywords should be used only when you analyze an image one box at a time, as the values will be loaded into the variables only for the last box analyzed.

SILENT is used to prevent printing of the output. This is helpful in procedures when variables are set.


next up previous index
Next: HISTOGRAM: Display a Histogram Up: Basic Image Analysis Previous: SKY: Compute the Modal   Index
Jon Holtzman 2002-02-13